Cowl flap operating mechanism



L. F. ENGELHARDT COWL FLAP OPERATING MECHANISM Dec. 7, 1948.

2 Sheets-Sheet 1 Filed June 25, 1945 m m F INVENTOR.

LLOYD F. ENGELHARDT BY 6 ATTOR Y i 0 \n 4 Q\ a v Q \w Ww/U/ y r PM A 3 .u L

Dec. 7, 1948. L. F. ENGELHARDT COWL FLAP OPERATING MECHANISM 2 Sheets-Sheet 2 Filed June 25, 1945 5 INVENTOR. LLOYD F. .ENGELHARDT ATTOR Y Patented Dec. 7, 194s anmyaenu-nngeiharat, Fergpson-,. -.Moi,;assigixor.:to: Curtiss-Wright Gorporation; -.a.-;conporationnof Delaware ioi i s. (cleatsee) 1 mis' invention relates to aircraft engine cowl fifips azidimore particularly to an improve'dvconnebfihgq means i'fbr operatively interconnecting acent' flaps' to assuresimultaneous movement thereof; 1 V I r 1h 'raidial aircraft engines, hinged-cowl flaps have customarily been providedito regulate the ramount of cboling-air :passingthrou'ghthe engine. Flaps= heretofore usedhave been interconnected 11y means ofbra'ckets and :connectinglinks movebly attaohed to-the flaps an'd cowl; with suitable m'eansafor actuating the flaps by one ori: more contml fmzonnectibn'st If the-"control connection beiwmesfdisengagew the ifiaps would 1 be free to iopen "on-lclbse and thereby interfere with the proper coool-ingtbf -t'he engine. l :iltfiis-itherefore .an object-of the present invenitio'n'zto provide an improved connecting means for +enginewc'owl tiflaps which is. extremely simple .in aconstruction, light-fin (weight and free of moving partsior :pivoted joints. Another object is to provide "ascowl flap'c'onnecting means which. will spermit iangularnmovement of adj acentsfiaps hav- -ixrgeitheir ihi'n'ge faxes rangularlyfdisposed in relaitiorrrtoieachfothenandiyet is of suchrigidity as itoma'useisimultaneousaangular movement of 'ad- Jj'acent: flapsbwhen. any flap is moved by; other :means: Aafurlther objectis to providela 'cowl fiap connecting-and actuating:meanssoarranged that 'zthesflaps willabeimovedto. a partially open position when ;the-zpri-mary -flap. operating: means is inoplerativei. A;sti1l.:further.;object is top-rovide a cowl flapzacnnnecting means vwhich will prevent overheating :of the: engine; when the vprimary flap actuating .meansffailslor becomes disconnected withtthe flaps inntheir closedposition;

'oltherz o jectsrand :advantages will be apparent from itheagfollowings detailed description a and ac- -tcompanyingkwdrawing, in which: Figure lisa pert spective. view; illustrating the improved flap l connectinew meansxasapplied to a cowl flap. assembly and as viewed from the interior of antengine'icowl iinstallatiom- Figure; 2 is a, transverse sectional wiew-ttakenion'lline 22. of Figural; Figure 3.is emotional-view taken longitudinally. of a-flapan'd :fais viewedialong 'line 3--3 of Figure, 1; and Figure theeconneoting;..means of this invention operativelytattaphed thereto. iflheepresentiinvention is shown cas'applied-ito- 'enginetcowlwvhich comprises :a zilorward cowl section It) surrounding an engine (not showmlin itheizusualnnanneraandispaced :longitudinally from m aiitgcowlzsection ,2! I :tmprovide lan engine T0661- iMqifiiI. onfletatliziitshowniiclosedi inuEigme: 3). 5'

liocated at rtheaaait end 'o'fzcowl. section L0 is.:the usual :cowl Bring 3ahaving'lifixed'ftheret'o inrspac'ed relationia plurality: .lo'fihingezfittings l4rtowhich are pivotally secured, as by bolts 45, -a plurality o'f fiaps; enerally :indicated' attlfi. :Eachrfiap 115 comprises aask-in or "outer section i iand aiformed -stiffeninginner: section l 8 suitablyspotwelded togetherin assembly to form a -lightweight; rigid flap-innit; suitably fastenedltotheiforwardpor- .fitting :89 havinyforwardly projecting clevi's por- -tions-' 21E: :for. pivotal 'engagement'-iwith th'e cowl hinge: fitting sl 4; One side portion. of the 'inn'er ja'centiflaps must; allowion'lateral relative moves' joegled-inwardly-1mm .the skin portion, as a l; tozprovide aaspace for receiving ithere'between Jone edge-0f: a. seal strip 22,

.the'eopposite :edge .of' which is secured to 8111166158 portion of an adja'centLilapalB.

Thwa'bove fdescribed: cowl and :flap 'structureiis of a relatiVely-mommon type andi. isnutilized=-.-ito regulateithe flow. oftair -past ithe engine-for cool- .:ing: purposes; i Such'.;reg.u1a'tion is effected by swinging :or: ang-ularly. positioning the flaps about the axis, (of 5. hinges M a to: control :the Jamountwt'of exittiair i'pass-ing through the 1 cowl :op'ening t2; r

I It: willbe sn'oted thattthetfiaps lfi arepositioned Iaround' athe cir'cnIar orcurved: cowl .11 e: :on-ihing'e l axes which are t'disposedin :ohords ofathe' transverse'icewl "curve. With: this :relation of parts'it willzbeeapparent rtha't: anyrconne ction 1b etwe en a dmentzoffthe 'flapswhen the'same are-moved anguila-rly aboutzitheir hinge axesforicoolingraincontrol.

It ha'si beenxthapracticeato' operatively conne'ct the iseveral flapssbyipivoteddirrkstandllevers ito assure simultaneous swingingxmovement of theaadjaoent flaps; Such prior:connecting mechanisms: are

.lAicomiectingemeansiovercomingathesabove'amenitioned'; faults oi l ipo'i'orflconnections a yet 1, satisfying :iallc-the;requirements for-isuchlconnections is indiecated generallysat iiiand'ishown rte lgoo'd advanctazgeein'sEigure 1.1a flhel cbnnectingsmeans-252mmplan ViEW-COfPOItiOHS lofaadjacentzfiaps with v prisesxdiverging: resilient arm's 5 constructed of -springtsteelfand securedttogether: at kith'eir :in-n'e'r mating ends 21 by rivets 282. "-Rlate elements :29

.:o.verlying :theyends 2"! zpreventzflexirrga'of then arm l-mallyrcausezifailure; ofiithe arm at the rivet :1li'o1e. To-Jthe outer; enldtiiifluof- 'eanh Lanna-2 Buis secured,

atrthezinnerlriveit:joint which s'fiexing :znorasz'bygrivets Silj "anupstanding:zplatesgportionz az *Ofiai Il'eshapedzarnounting bracketfliu Theeba'se eplatei3dautrlthe .btaeaetaes isssecured tmtneeflat motion transmitted to the flap by this rod will be transmitted to the other flaps by the novel connecting means 25 which preferably operatively connect all the flaps. It will be seen that any combination of primary operating connectionsand the connectors 25 of this invention may be made to suit the requirements of-the installation.

The spring arms 26 are so assembled and installed that the arms are in their unflexed or unstressed condition when the flaps are partially open as shown in Figure 1. As the flaps tend to close, their adjacent edgestend to approach each other, as shown in Figure 4, because of the angular disposition of their hinge axes. Unless acted upon by some outside force, such as the primary operating means 38, this closing movement is resisted or prevented by flexure of the spring arms 26 to a stressed condition. A similar" situation occurs if the flaps tend to open further from the partially open position shown in Figure 1. Thus, if any failure or disconnection occurs tinned engine cooling air flow and prevent damage to theengine by overheating.

At the same time, it will be noted that the spring arms 26 are not permitted any relative movement, except flexure, with respect to the Thus, pivotal movement is prevented of attachment. This arrangement insures that,

if thereis any angular movement of a flap with respect to its hinge axis, it must be accompanied by an equal angular movement of all other flaps connected thereto by the connecting means 25.

The flexibility of the arms 25 will thus allow relative lateral movement of adjacent flaps caused by the angular relation of their pivot axes, and yet is rigid in a plane relatively transverse of such pivot axes to assure simultaneous angular movemerit of the adjacent flaps about their hinge axes. It will be seen that transfer of motion from one flap to an adjacent flap is. resisted in shear by the leaf arms 25, while convergence and divergence of adjacent flaps in closing and opening; 1). 'is accompanied by bending, and to a slight extent by twisting, of the arms. As the leaf arms are relatively wide and thin, with their major crosssectional dimensions extending in the direction of the shearing stresses, the mechanism is relatively rigid in its function of transferring motion be- The minor cross-sectional dimension of each leaf arm, being in the direction of the bending stresses, allows movement of 'the flaps with relatively light spring resistance, the;

degree of such resistance being, of course, dependent upon the thickness and inherent stifiness of the leaf arms. 5

It will also be noted that the arms 25 in .the

illustrated embodiment extend outwardly with.

.arms 25 at their connection points 2-8 are in the primary operating means, the flaps will be moved to a partially open position to allow con- 4 loads in shear, rather than torsional loads as would be the case if the connection points were disposed at or adjacent the flap pivot axes.

It is understood that changes may be made in the above described embodiment of the invention without departing from the spirit thereof, except as defined in the appended claims.

1. In a cowl flap installation having 'a pair of flaps with their hinge axes angularly related but in a substantially common plane, a primary operating means for moving at least one of the flaps about its hinge axis, and means for effecting substantially equiangular movement of the flaps about their hinge axes comprising a leaf spring affixed at one end to each flap, the opposite ends of the leaf springs being connected, each leaf spring being arranged with its major cross-sectional dimension substantially in the direction of movement of the springs about said axes, the direction of extent of each leaf spring, from the end thereof afiixed to the flap to the opposite end thereof connected to the other-leaf spring, being generally away from the hinge axis of the related flap, and the springs being arranged to resist by their-resilience hinging movement of the flaps from a partially open position. i

2. In a cowl flap installation having a pairof flaps with their hinge axes, angularly related but in a substantially common plane, meansjior effecting substantially equiangular movementof the flaps about their hinge; axes comprising a leaf spring affixed at one end to each flap, theopposite endsof the leaf springs being connected, each leaf spring being arranged with its major cross sectional dimension substantially. i n-,. its plane of movement with the related flap, andthe direction of extent of each leaf spring, from the end thereof affixed to the flapto the opposite endthereof con-- nected to the other leaf spring, beinggenerally away from the hingeaxis of the related fiapzizq 3. In a cowl flap installationghavinga.pair.;of flaps with their hinge axes angularlyrelatedzbut in a substantially common plane,-means for of resting substantially equiangular movementjof the flaps about their hinge axes comprisinga spring unit of substantially V formation with the'vertex of the V directed awa'ytfrom the. hinge axesand one arm of the V affixed to each of said'flaps. 4. In a cowl flap installation having a-pair'of flaps with their hinge axes angularly related but in a substantially common plane, means foreftheir hinge axes comprising a spring unit of return directed formation with the arms thereof extending from the bight portion thereof in a direction substantially toward saidaxes and'ithe end portions of said arms beingaflixed. to the flaps. I

6. In a cowl fiap installation havinga pair of fiapswith their hinge axes angularly. related but in a common plane means for effecting substantially equiangular movement of the flaps about their hinge axes comprising a spring unit of return directed formation with the arms thereof extending from the bight portion thereof in a direction substantially toward said axes, and the end portions of said arms being afiixed to the flaps, each arm being of elongated cross-section with the major dimension thereof extending substantially in the plane of movement of the spring unit about the hinge axes.

7. In combination with a pair ofhinged elements whose hinge axes are angularly related but in a'common plane, means for effecting substantially equiangular movement of the hinged elements about said axes comprising a pair of leaf springs connected to each other at one end and each rigidly connected at the opposite end thereof to a different one of said hinged elements, each leaf spring having its major cross-sectional dimensions substantially in the direction of movement of the springs about the hinge axes, the direction of extent of the springs from the ends thereof that are connected to each otherto said opposite ends thereof being in general toward said hinge axis.

LLOYD F. ENGELHARDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name I Date 2,049,751 Shoemaker Aug. 4, 1936 2,124,333 Duff et a1 July 19, 1938 2,303,732 Follick Dec. 1, 1942 FOREIGN PATENTS Number Country 7 Date 480,478 Great Britain Feb. 23, 1938 

